Most people in the U.S.A. and Canada send me checks. My
bank can process checks from USA and Canadian banks with
the tracking number codes on the bottom. Many people
in Europe have send me USA bills (they get them from tourists, no doubt)
wrapped in several layers of paper to conceal them.

I am actually not going through strings a lot these days...
I am saving up for a new lute which might be delivered in the next
year or so!

There is no obligation to pay me! Only if you want to.

I have also gotten..

A proof set of coins, in a nice plastic display case

German money from the WW2 era

Many Euro bills from different countries (which aren't as interesting as
the old money.)